Heavy Metals and the Alternate Bearing Effect in the Date Palm ( Phoenix dactylifera)

Abstract

The alternate bearing effect is when plants produce abundant crops of fruit in some years, but sparse yields in others. This review summarises recent studies that suggest a connection between the alternate bearing effect in the date palm, Phoenix dactylifera, and the presence of certain chemical elements (mostly metals) in the tree tissues. So far, there is evidence that levels of Ag, B, Ba, Ca, Cd, Cu, Fe, K, La, Mg, Mn, N, Na, Se, Tl, and Zn in the dates and leaflets are affected by the al-ternate bearing phenomenon. The significance of this work, therefore, emphasises the prospect of using our experimental data to overcome sparse yields, due to the alternate bearing effect, and producing more prolific growth of fruits. The potential agricultural, economic, environmental and health implications of these findings are considered.